electron cloud
DESCRIPTION
SUBATOMIC PARTICLE. LOCATION (in the atom). RELATIVE CHARGE. MASS (amu). In nucleus. Proton. +1. 1. Neutron. In nucleus. 0. 1. Electron. electron cloud. -1. 0. Do Now : First fill in the table below. Which one of these particles is NOT counted in the mass number?. - PowerPoint PPT PresentationTRANSCRIPT
Do Now: First fill in the table below.Which one of these particles is NOT counted in the mass number?
0-1electroncloud
Electron
10In nucleusNeutron
1+1In nucleusProton
MASS(amu)
RELATIVECHARGE
LOCATION(in the atom)
SUBATOMIC PARTICLE
Do Now: First fill in the table below.Which one of these particles is NOT counted in the mass number?
0-1electroncloud
Electron
10In nucleusNeutron
1+1In nucleusProton
MASS(amu)
RELATIVECHARGE
LOCATION(in the atom)
SUBATOMIC PARTICLE
3 x 2 = 6 H atoms
Interpretation of a Chemical Formulas1 molecule of sulfuric acid
H2SO4
Two atomsof hydrogen
One atom of sulfur
Four atoms of oxygen
HH
O
S
OO
O
How many hydrogen atoms are in three molecules of sulfuric acid?
3 x 2 = 6 H atoms
Interpretation of a Chemical Formulas1 molecule of sulfuric acid
H2SO4
Two atomsof hydrogen
One atom of sulfur
Four atoms of oxygen
HH
O
S
OO
O
How many hydrogen atoms are in three molecules of sulfuric acid?
Models of the Atom
Dalton’s model (1803)
Thomson’s plum-pudding model (1897)
Rutherford’s model (1909)
Bohr’s model (1913)
Charge-cloud model (present)
Dorin, Demmin, Gabel, Chemistry The Study of Matter , 3rd Edition, 1990, page 125
Democritus’s model
(400 B.C.)
1800 1805 ..................... 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945
1803 John Dalton pictures atoms astiny, indestructible particles, with no internal structure.
1897 J.J. Thomson, a Britishscientist, discovers the electron,leading to his "plum-pudding" model. He pictures electronsembedded in a sphere ofpositive electric charge.
1904 Hantaro Nagaoka, aJapanese physicist, suggests that an atom has a centralnucleus. Electrons move in orbits like the rings around Saturn.
1911 New Zealander Ernest Rutherford statesthat an atom has a dense,positively charged nucleus. Electrons move randomly in the space around the nucleus.
1913 In Niels Bohr'smodel, the electrons move in spherical orbits at fixed distances from the nucleus.
1924 Frenchman Louis de Broglie proposes thatmoving particles like electronshave some properties of waves. Within a few years evidence is collected to support his idea.
1926 Erwin Schrodinger develops mathematicalequations to describe the motion of electrons in atoms. His work leads to the electron cloud model.
1932 James Chadwick, a British physicist, confirms the existence of neutrons, which have no charge. Atomic nuclei contain neutrons and positively charged protons.
+--
--
-e
ee
+
+ +
+
++
++
e
eee
e
ee
Isotopes = atoms of the same element
with different mass numbers (because they have different #’s of
neutrons)
B115
Mass #
Atomic #
Atomic symbol:
Hyphen notation: boron-11
(protons + neutrons)
(only protons)
FILL IN THE BLANKS BELOW… = proton = neutron (no electrons shown)
# of # of atomic massProtons neutrons number number symbolA
B
FILL IN THE BLANKS BELOW… = proton = neutron (no electrons shown)
# of # of atomic massProtons neutrons number number symbolA
B
5 5 5 10
5
B
10
5 6 5 11
5
B
11
What’s the hyphen notation for A? boron-10
FILL IN THE BLANKS BELOW… = proton = neutron (no electrons shown)
# of # of atomic massProtons neutrons number number symbolA
B
5 5 5 10
5
B
10
5 6 5 11
5
B
11
What’s the hyphen notation for A? boron-10
Let’s compare carbon-12 & carbon-14
+
+
+
+
+
+
Nucleus
Electrons
Carbon-12
Neutrons 6Protons 6Electrons 6
+
+
+
+
+
+
Carbon-14
Neutrons ?Protons 6Electrons 6
Nucleus
Electrons
How many neutrons are in carbon-14? 8 n
Let’s compare carbon-12 & carbon-14
+
+
+
+
+
+
Nucleus
Electrons
Carbon-12
Neutrons 6Protons 6Electrons 6
+
+
+
+
+
+
Carbon-14
Neutrons 8Protons 6Electrons 6
Nucleus
Electrons
How many neutrons are in carbon-14? 8 n
Atomic # C126
Mass #Carbon-12
Atomic # C146
Mass #Carbon-14
Isotopes – reviewHow many neutrons in chlorine-37?
20 n Chlorine-37
atomic #: 17
mass #: 37
# of protons: 17
# of electrons: 17
# of
neutrons: ???
Cl3717
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
Isotopes – reviewHow many neutrons in chlorine-37?
20 n Chlorine-37
atomic #: 17
mass #: 37
# of protons: 17
# of electrons: 17
# of neutrons: 20
Cl3717
Courtesy Christy Johannesson www.nisd.net/communicationsarts/pages/chem
IONS Ions are atoms that have lost or gained electrons.
An atom that loses an electron becomes a positive ion (CATION)
An atom that gains an electron becomes a negative ion (ANION)
REVIEW OF SUB/SUPER-SCRIPTS
Echarge
formulaatomic #
mass #
HOMEWORK – #’s 29-33,38,40
EXAMPLES OF IONS
1.A magnesium atom loses two e- and becomes which cation?
Mg2+
12 protons 12 neutrons (usually) 12 electrons
EXAMPLES OF IONS
A magnesium atom loses two e- and becomes which cation?
Mg2+
12 protons 12 neutrons (usually) 10 electrons
EXAMPLES OF IONS
A chlorine atom gains one e-
and becomes which anion?
Cl1-
17 protons 18 neutrons (usually) 17 electrons
EXAMPLES OF IONS
A chlorine atom gains one e-
and becomes which anion?
Cl1-
17 protons 18 neutrons (usually) 18 electrons
EXAMPLES OF IONS
If magnesium and chloride bond together, what’s the formula of the compound they form?
MgCl2 magnesium chloride…
more on this next chapter
EXAMPLES OF IONS
If magnesium and chloride bond together, what’s the formula of the compound they form?
MgCl2 magnesium chloride…
more on this next chapter